Best low-boost turbo choice for 1HZ? (6 Viewers)

[lelandEOD]

I’m almost afraid to ask this question as I know it’s a topic fairly beat to death on this forum. I’ve done several searches and haven’t been able to find a simple and direct answer to the question I have.

I’m putting a 1HZ in my 40 series and have had several buddies recommending I add a turbo to compensate for high-altitude and to run it cooler. It seems I have a few options and I have absolutely no idea which one would be best. Factors:

1. Since I’m not after added power, I don’t need/want a high-boost turbo and do not plan to turn up the fuel (however, my IP currently has a NA high altitude compensator installed so it may require some adjustment?).

2. Several local guys have recommended I look for a setup putting out something modest, like 8 to 10psi?

3. I will Add a pyro and boost gauge to my Dakota Digital HDX for monitoring.

Problem:

There doesn’t seem to be a lot in between the $150 CHICOM crap-shoots on eBay and the super expensive G-Turbos (way overkill for my application). I need some input from you folks on what would be best suited for my intended application.

What would be the best course of action here? I could obviously swap out a cheap Chinese turbo every 3 to 5 years and it would still be cheaper in the long run then a new Toyota when HDT turbo. However, I absolutely will not risk a catastrophic blade ingestion just to save a few bucks upfront. Would I be best served waiting to find a used factory CT26 and rebuild it?

Or is there another aftermarket (Garrett or similar) option that would suit my application?


Turbo selection is overwhelming as I have no experience with them. There are so many factors that go into selecting the right one it makes my head spin.

 

[Mighty690]

You might want to contact Michael Hein at westcoastcruisers.com in Ramona, CA. He knows diesel cruisers well and has done his own turbo systems to boot. He's got a couple 1HZ powered vehicles too.

 

[77cruiser77]

keep it stock or swap in a 1HDT instead. Turbocharging a 1HZ isn't cheap to do it properly and in the end its still indirect injection

 

[IanB]

Factory take-off 1HD-FTE turbo set to 10-15psi, improved low end response and high flow compared to 1HD-T/1HD-FT and still OEM quality and reliability. I'm not sure on a 1HZ-T, but on a 1HD-T auto setup 10psi is maxed out at 100km/h on flat land, to go faster you're just adding more fuel after that. Being that you're in the mountains, a bit more boost will go a long way in making it easier to drive.

 

[JuanJ]

Hello,

A low pressure (10 psi) turbo will do. Otherwise you will put too much stress on the engine. The 1HZ is bulletproof but in long term cannot handle the temperatures that medium- or high-pressure turbos generate.

A Toyota turbo is preferable. The more Toyota components you have, the easier it is to operate, troubleshoot and repair your Cruiser, in my book.

Some Coaster buses, model year 1992 to 1996 if I remember correctly (please double check) had a 1HZ engine with a turbo in this setup type. The mythical 1HZ-T. It is possible to find all the parts and go that way. That is what I would do.

@damienperu did this conversion in an HZJ78. Look in the 70 Series forum for details.

It would be cool to see a 40 Series with an 1HZ-T.





Juan

 

[DamoPeru]

the 1HZ-T turbo wastegate cuts in at 8psi, so that's what toyota thought the 1HZ can handle, albeit with a lower compression like the 1HD-T. I have been really happy with my conversion, best of both worlds in many respects, but i wouldn't recommend going to the expense of the 1HZ-T turbo unless you rebuild the motor so you can replace all the other 1HZ parts with the 1HZ-T equivalents. Not a cheap option, but i did it to have maximum reliability and drivability at high altitude.

 

[DamoPeru]

Some Coaster buses, model year 1992 to 1996 if I remember correctly (please double check) had a 1HZ engine with a turbo

01/1993 - 04/1996, incomplete coaster chassis sold to bus fabricators in Europe

 

[mudgudgeon]

I disagree with the low boost theory.

7-10psi is common for HZ turbo installs, but it's a legacy from the early 90s. Turbo technology, and understanding of tuning and failures modes for these engines has come a long way since 1990.
There's 25yrs experience turbocharging HZs in Aus. Common denominator in failures seems to regularly be tuning without measuring AFRs, or EGTs, and running too much fuel and low boost.

Boost helps control EGTs. High combustion temps in a 1HZ will kill it far sooner than boost.

The problem with running low boost is it provides just enough kick to enable you to dial in too much fuel. It can give you a decent little power increase but at the expense of high combustion temps and smokey exhaust at high load, low RPM conditions.
If a turbo 1HZ was tuned for safe EGTs, safe AFRs and 8psi, its still going be lack lustre in the performance stakes.

For the same outlay, choose a turbo that gives you a low RPM spool up, high airflow, and around 15-20 psi of boost.

With the right turbo, you can have torque from 12-1300rpm, power right through the rev range, and enough airflow to be able to add a decent amount of fuel, but keep combustion temps in check.

 

[fitzmooney]

What he said.
I have been running a 2H for 8 years with 15lb boost and fuel maxed out at 600C with no problems.

 

[1HaytchZed]

What is the correlation of EGT to Combustion Chamber temps?

How does one monitor AFR on the 1HZ?

 

[lelandEOD]

Thanks for the feedback, gents. So it doesn't sound like there is one widely agreed upon solution for what I intend to do. Again, I'm sure it can be tempting to up the fuel as it's just a turn of a screw but I'm not looking for performance here; rather, extended life and better burn at altitude. I'll probably just run the truck NA for a while anyway, but I've learned that it can save you a lot of time, money, and hassle, to develop a clear picture of your ultimate goals well in advance. If I know I was definitely going for a turbo setup, I would drill and tap the block while I've got it on the engine stand for BEBs.

I think I'll follow Mighty690's advice and call a few specialty shops for guidance.

P.S.,
Damien, I enjoyed the hell out of the mythical hunt for the factory 1HZ-T thread as well as your build thread.

 

[mudgudgeon]

What is the correlation of EGT to Combustion Chamber temps?

How does one monitor AFR on the 1HZ?

EGTs measured in the manifold, pre turbo are used as the most reliable indicator of combustion temps. There's a large drop in temperature by the time gas has past through the turbine. You'd get more accuracy having a pyro probe right at the exhaust port, but from a practical point of view, installing a probe before the turbo flange is easier, and works.

AFRs can be measured during tuning with a temporary probe in the tail pipe, or via a weld in bung in the exhaust and a temporary, or permanent probe installed.
I think using AFRs is a good tuning device. EGTs give you a moment by moment indicator of view hard you're working the engine at anytime, though an AGR gauge can too.

 

[mudgudgeon]

@lelandEOD if you have a spare few days, read through the "official 1HD-T tuning" thread, and the "Gturbo alternative tech" threads.
Loads of robust info and discussion relevant to your engine

 

[JuanJ]

Thanks for the feedback, gents. So it doesn't sound like there is one widely agreed upon solution for what I'm intending to do. Again, I'm sure it can be tempting to up the fuel as it's just a turn of a screw but I'm not looking for performance here; rather, extended life and better burn at altitude. I'll probably just run the truck NA for a while anyway, but I've learned that it can save you a lot of time, money, and hassle, to develop a clear picture of your ultimate goals well in advance. If I know I was definitely going for a turbo setup, I would drill and tap the block while I've got it on the engine stand for BEBs.

I think I'll follow Mighty690's advice and call a few specialty shops for guidance.

P.S.,
Damien, I enjoyed the hell out of the mythical hunt for the factory 1HZ-T thread as well as your build thread.

Hello,

Good choice.

What is the altitude in your neck of the woods? Your IP compensator will be able to handle it without tampering with the fuel screw. Keep in mind that as altitude increases, available oxygen to burn the extra fuel decreases and you end up with higher temperatures (an unwanted byproduct of incomplete combustion) and black smoke. Diesel engines do not like extra heat.

On the other hand, the 1HZ engine has roughly the same power as the 2F. Enough grunt to move a 40 Series Cruiser around, altitude aside, in my humble opinion, while a decision is made about the turbo.

Last but not least, a 1HZ is a big engine. It is a tight fit in an 40 Series.

Looking forward to see your build.





Juan

 

[lelandEOD]

Hello,

Good choice.

What is the altitude in your neck of the woods? Your IP compensator will be able to handle it without tampering with the fuel screw. Keep in mind that as altitude increases, available oxygen to burn the extra fuel decreases and you end up with higher temperatures (an unwanted byproduct of incomplete combustion) and black smoke. Diesel engines do not like extra heat.

On the other hand, the 1HZ engine has roughly the same power as the 2F. Enough grunt to move a 40 Series Cruiser around, altitude aside, in my humble opinion, while a decision is made about the turbo.

Last but not least, a 1HZ is a big engine. It is a tight fit in an 40 Series.

Looking forward to see your build.





Juan

I live at about 5000ft but frequently travel up to 8k+.

The engine does have the NA high altitude compensator on it but I was told a turbo was still a good idea to cram a bit of O2 into the charge.

 

[DamoPeru]

Damien, I enjoyed the hell out of the mythical hunt for the factory 1HZ-T thread

yeah, by far my favorite thread on MUD, it was like finding the holy grail!

 

[lelandEOD]

...Looking forward to see your build.


Juan

I’m really looking forward to it too.

 

[JuanJ]

I live at about 5000ft but frequently travel up to 8k+.

The engine does have the NA high altitude compensator on it but I was told a turbo was still a good idea to cram a bit of O2 into the charge.

Hello,

The altitude compensator, well maintained, helps a lot.

On the other hand, I have seen many diesels die from too much fuel (from tampering with that screw at the IP) at mid to high altitude. This is why I do not like to mess with the fuel setting too much.

Diesel engines suffer from lack of oxygen at altitude but do not like high operation temperatures. This is especially true for the 1HZ. However, a little more oxygen from a low pressure turbo is enough to keep the balance between extra power at an altitude and operating temperature. It is just a question of doing it right.







Juan

 

[Mighty690]

Thanks for the feedback, gents. So it doesn't sound like there is one widely agreed upon solution for what I'm intending to do. Again, I'm sure it can be tempting to up the fuel as it's just a turn of a screw but I'm not looking for performance here; rather, extended life and better burn at altitude. I'll probably just run the truck NA for a while anyway, but I've learned that it can save you a lot of time, money, and hassle, to develop a clear picture of your ultimate goals well in advance. If I know I was definitely going for a turbo setup, I would drill and tap the block while I've got it on the engine stand for BEBs.

I think I'll follow Mighty690's advice and call a few specialty shops for guidance.

P.S.,
Damien, I enjoyed the hell out of the mythical hunt for the factory 1HZ-T thread as well as your build thread.

I just had dinner with Michael Hein of westcoastcruisers.com and I brought up this post. He knows what you want to do. Reach out to him for a better explanation.
Scot

 

[lelandEOD]

I just had dinner with Michael Hein of westcoastcruisers.com and I brought up this post. He knows what you want to do. Reach out to him for a better explanation.
Scot

I called him a few days ago and left a message. I’ll try him again today. Thanks!

Lee